Gesture input device

ABSTRACT

An input device includes: a movement detector that detects a user movement; and an image projector that forms a zone image in a space to present a region where the movement detector detects movement; and the image projector includes a first light source; and a first light guide plate which includes a light emitting surface and directs light entering from the first light source so that the light exits from the light emitting surface and forms an image in a space.

FIELD

The present invention relates to a gesture input device that allowsinput via user movement.

BACKGROUND

Japanese Patent Publication No. 2015-184841 (published 22 Oct. 2015)discloses a gesture input device that detects a specific part of auser's body (e.g., the user's finger) and performs an operation on avehicle instrument on the basis of the movement of said specific part.The movement of the above mentioned specific part can be detected, forinstance, via a near-infrared sensor that produces a three-dimensionalimage. The near-infrared sensor has a predetermined region that is thedetection area and detects the movement of the finger when the user'sfinger enters the detection area.

However, the user may unable to provide suitable input to the gestureinput device disclosed in JP 2015-184841 A since the user is unable torecognize the detection area of the gesture input device.

Embodiments of the present invention implement a gesture input devicethat allows the user to recognize the area accepting an input action.

SUMMARY

To address the foregoing a gesture input device according to anembodiment of the present invention includes: a movement detectorconfigured to detect a user movement; and an image projector configuredto form a zone image in a space to present a region whereat the movementdetector is configured to detect movement. The image projector includesa light source; and a light guide plate which includes a light emittingsurface and is configured to direct light entering from the light sourceso that the light exits from the light emitting surface and forms animage in a space.

In the above-described configuration, the image projector forms a zoneimage in a space to present a region whereat the movement detector isconfigured to detect movement. The light source and the light guideplate are in the image projector, and light entering from the lightsource is directed by the light guide plate to exit from the lightemitting surface and form an image in a space. Accordingly, the user canrecognize where the input device accepts input actions via presentationof an input location image formed in a space, and appropriately performan input action.

The gesture input device according to another embodiment furtherincludes a determination unit configured to assess whether or not themovement detected by the movement detector is an input actionrepresenting a predetermined input; and an assessment resultpresentation unit configured to present an assessment result from thedetermination unit.

With the above-described configuration the determination unit assessesthe movement detected by the movement detector, and the assessmentresult presentation unit presents the assessment result. Accordingly, auser may reference the assessment result to verify whether the inputaction was assessed as the desired input.

The assessment result presentation unit in a gesture input deviceaccording to another embodiment includes a second light guide plateconfigured to direct light entering from the plurality of second lightsources so that the light exits therefrom and forms an image in a space.

In the above-described configuration, the assessment result from thedetermination unit is presented as an image formed in a space via thesecond light source and the second light guide plate.

In a gesture input device according to another embodiment, the lightguide plate and the second light guide plate are stacked.

The above-described configuration reduces the size of the gesture inputdevice.

The assessment result presentation unit in a gesture input deviceaccording to another embodiment may include: a plurality of second lightsources; and a second light guide plate configured to direct lightentering from the plurality of second light sources so that the lightexits therefrom and forms an image in a space; and when the movementdetected by the movement detector is an input action representing apredetermined input, the assessment result presentation unit activates asecond light source among the plurality of second light sourcescorresponding to said input action to cause a different imagecorresponding to the input action to be formed in a space.

According to the above-described configuration, different images may beformed in a space by switching to a second light source in response tothe input action and causing that light to enter the second light guideplate.

In a gesture input device according to another embodiment, the directionfrom which light is incident on the second light guide plate is thedifferent for the plurality of second light sources.

According to the above-described configuration, different images may beformed in space by causing light to enter from different directions.

In a gesture input device according to another embodiment, the directionfrom which light is incident on the second light guide plate is the samefor the plurality of second light sources and the second light sourcesare mutually isolated.

According to the above-described configuration, different images may beformed in space by causing light to enter from different locations.

EFFECTS

A gesture input device according to embodiments of the present inventionallows a user to recognize the area accepting an input action.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating the main components of an inputdevice according to a first embodiment of the present invention;

FIG. 2 is a perspective view of a display unit provided to theabove-mentioned input device;

FIG. 3 is a perspective view of the above-mentioned input device in use;

FIG. 4A to FIG. 4C are examples of input location images presented bythe above-mentioned display unit;

FIG. 5 is a block diagram illustrating the main components of an inputdevice according to a second embodiment of the present invention;

FIG. 6 is a perspective view of the above-mentioned input device in use;

FIG. 7A is an example of a three-dimensional image presented when theassessment result of a determination unit is presented as athree-dimensional image; FIG. 7B is an example of a second display unitcapable of presenting two types of three-dimensional images via a singlelight guide plate;

FIG. 8A illustrates an example configuration of a second display unitwhen an assessment result from a determination unit is presented as atwo-dimensional image; FIG. 8B is a perspective view illustrating aconfiguration of an optical-path changing portion 16;

FIG. 9 is a perspective view of a third embodiment of the input devicein use;

FIG. 10A illustrates an example of an input device according to thefirst embodiment installed in an elevator; FIG. 10B illustrates anexample of an input device according to the first embodiment installedin a refrigerator; FIG. 10C is an example illustrating an input deviceaccording to the first embodiment installed in a game machine;

FIG. 11A is a cross-sectional view illustrating an example configurationof a display unit according to a fifth embodiment; FIG. 11B is a planview illustrating the configuration of a light guide plate provided inthe display unit illustrated in FIG. 11A;

FIG. 12 is a perspective view illustrating how the display unitillustrated in FIG. 11A produces a stereoscopic image;

FIG. 13A is a perspective view of a display unit of a fifth embodimentthat is distinct from the display unit in FIG. 11A; FIG. 13B is across-sectional view illustrating a configuration of the display unit inFIG. 13A; and

FIG. 14 is a cross-sectional view illustrating a display unit of thefifth embodiment that is distinct from the display units illustrated inFIG. 11A and FIG. 13A.

DETAILED DESCRIPTION First Embodiment

An input device 1 (gesture input device), which is an embodiment of thepresent invention is described below in detail.

Configuration of the Input Device 1

FIG. 1 is a block diagram illustrating the main components of an inputdevice 1 according to a first embodiment; as illustrated in FIG. 1, theinput device 1 is provided with a display unit 10, a movement detector20, and a controller 30. The display unit 10 includes a light guideplate 11 (i.e., a first light guide plate) and a light source 12 (i.e.,a first light source). The controller 30 includes a display controller31 and a determination unit 32.

The display unit 10 (i.e., an image projector) forms an input locationimage (i.e., a zone image) in a space to present the region in which themovement detector 20 is configured to detect movement. A specificconfiguration of the display unit 10 is described below.

FIG. 2 is a perspective view of the display unit 10. FIG. 2 illustratesa state where the display unit 10 presents a stereoscopic image I; morespecifically the display unit 10 displays a button-shaped stereoscopicimage I along with the letters “ON”.

The light guide plate 11 is a transparent rectangular resin materialwith a relatively high refractive index. The light guide plate 11 may beproduced from, for instance, a polycarbonate resin, a poly methylmethacrylate resin, glass or the like. The light guide plate 11 isprovided with an emission surface 11 a (i.e., a light emitting surface)that outputs light, a rear surface 11 b opposing the emission surface 11a, and four end surfaces 11 c, 11 d, 11 e, 11 f. The end surface 11 c isan incidence surface wherethrough light projected from the light source12 enters the light guide plate 11. The end surface 11 d opposes the endsurface 11 c; and the end surface 11 e opposes the end surface 11 f;light entering the light guide plate 11 from the light source 12 isdirected by the light guide plate 11 to exit from the emission surface11 a and produce an image in a space. The light source 12 may be a lightemitting diode, for example.

A plurality of optical-path changing portions 13 are formed on the rearsurface 11 b of the light guide plate 11 including an optical-pathchanging portion 13 a, an optical-path changing portion 13 b, and anoptical-path changing portion 13 c. The optical-path changing portions13 a, 13 b, and 13 c are formed along the lines La, Lb, and Lcrespectively. Here the lines La, Lb, and Lc are straight lines that aresubstantially parallel to the Z axis direction. Any given optical-pathchanging portion 13 is formed sequentially for the most part along the Zaxis direction. In other words, the plurality of optical-path changingportions 13 is formed along predetermined lines in a plane parallel tothe emission surface 11 a.

Light projected from the light source 12 and directed by the light guideplate 11 is incident at each position of the optical-path changingportions 13 along the Z axis direction. The optical-path changingportions 13 cause light incident at each location thereof tosubstantially converge at a fixed point corresponding to theoptical-path changing portion 13. The optical-path changing portions 13a, 13 b, and 13 c in particular are illustrated in FIG. 2 as a portionof the optical-path changing portions 13. FIG. 2 further illustrates theoptical-path changing portions 13 a, 13 b, and 13 c in a state where theplurality of light beams exiting therefrom converge.

More specifically, the optical-path changing portion 13 a corresponds toa fixed point PA in the stereoscopic image I. Light exiting from eachlocation of the optical-path changing portion 13 a converges at thefixed point PA. Therefore, the optical wavefront from the optical-pathchanging portion 13 a appears as an optical wavefront that is radiatingfrom the fixed point PA. The optical-path changing portion 13 bcorresponds to a fixed point PB in the stereoscopic image I. Lightexiting from each position of the optical-path changing portion 13 bconverges at the fixed point PB. Thus, any of the optical-path changingportions 13 cause light incident at each location thereof tosubstantially converge at a corresponding fixed point. Thus, any of theoptical-path changing portions 13 may present an optical wavefront thatappears to radiate from a corresponding fixed point. The optical-pathchanging portions 13 correspond to mutually different fixed points. Thegrouping of a plurality of fixed points corresponding to theoptical-path changing portions 13 produces a stereoscopic image I in aspace which can be perceived by a user. More specifically, thestereoscopic image I is produced in a space near the emission surface 11a in relation to the light guide plate 11.

The display controller 31 controls the presentation of the inputlocation image shown by the display unit 10. For example, the displaycontroller 31 controls activating and deactivating the light source 12provided to the display unit 10 to thereby control presenting or hidingthe input location image. Additionally, the display controller 31 mayadjust the brightness when the light source 12 includes a function forcontrolling the brightness thereof.

The movement detector 20 detects the movements of the user. The movementdetector 20 may be an imaging device that employs, for example, acharge-coupled device (CCD) or a complementary metal oxide semiconductor(CMOS). In addition, the movement detector 20 may be a near-infraredsensor.

The determination unit 32 assesses whether or not the user movementdetected by the movement detector 20 is an input action representing apredetermined input. An input action is a preliminarily determinedmovement established in the input device 1 as a movement representing aninput.

FIG. 3 is a perspective view of the above-mentioned input device 1 inuse. In the example illustrated in FIG. 3 the light guide plate 11 andthe light source 12 produce a two-dimensional image of a rectangle,i.e., an input location image P1 that appears to float in a space infront of the light guide plate 11. The input location image P1 is formedwithin a space where the movement detector 20 can detect a user'smovements. The user may provide input to the input device 1 byperforming a predetermined input action at the location of the inputlocation image P1; more specifically, the user may provide input as iftouching the input location image P1 with the hand H. More practicallythe input device 1 accepts input actions in a space in the inputlocation image P1 where it is conceivable that the hand H would touch;in other words, in the space indicated by the dotted lines in FIG. 3.

FIG. 4A to FIG. 4C are examples of input location images presented bythe display unit 10; FIG. 3 depicts a rectangular frame that representsthe input location image presented by the display unit 10. However, theinput location image is not limited to a rectangle.

The input location image may be a circle when presented as atwo-dimensional image as illustrated in FIG. 4A, or a sphere whenpresented as a three-dimensional image. The input location image mayalso be a coordinate axis when presented as a two-dimensional image asillustrated in FIG. 4B, or a right-angled parallelepiped when presentedas a three-dimensional image as illustrated in FIG. 4C. The inputlocation image may be a two-dimensional or three-dimensional imagedifferent from the images depicted in FIG. 4A through FIG. 4C.

If the input location image is a two-dimensional image, the user maysimply perform an input action at a location that is in contact with theplane represented by the two-dimensional image. If the input locationimage is a three-dimensional image, the user may simply perform an inputaction in the space represented by the three-dimensional image.

As above described, the display unit 10 in the input device 1 forms aninput location image that presents the region wherein the movementdetector 20 can detect a user movement. The display unit 10 includes thelight source 12 and the light guide plate 11. Light entering the lightguide plate 11 from the light source 12 is directed by the light guideplate 11 to exit from the emission surface 11 a and produce an image ina space. Accordingly, the user can recognize where the input device 1accepts input actions via presentation of the input location imageformed in a space, and appropriately perform an input action.

Second Embodiment

An input device 2 (gesture input device), which is another embodiment ofthe present invention is described below in detail. For the sake ofconvenience, components previously described in an embodiment that havean identical function are given the same reference numerals, andexplanations therefor are omitted.

FIG. 5 is a block diagram illustrating the main components of an inputdevice 2 according to an embodiment of the present invention; asillustrated in FIG. 5, the input device 2 differs from the input device1 as follows:

the presence of a second display unit 40 (i.e., an assessment resultpresentation unit); and

the presence of a controller 30A instead of the controller 30.

The second display unit 40 includes a light source 42 (i.e., a secondlight source), and a light guide plate 41 (i.e., a second light guideplate) that directs light entering from the light source 42 and causesthe light to exit therefrom and form an image in a space. A controller30A includes the functional components of the controller 30 as well as asecond display controller 33.

The second display unit 40 presents the assessment results from thedetermination unit 32. That is, the second display unit 40 forms aninput assessment image in a space with the input assessment imagerepresenting the assessment results from the determination unit 32. Morespecifically, if the determination unit 32 determines that the usermovement detected by the movement detector 20 is an input action, thesecond display unit 40 forms an image corresponding to the assessmentresult. Note that since the second display unit 40 and the display unit10 have identical configurations, further detailed descriptions of thesecond display unit 40 are omitted.

The second display controller 33 controls the presentation of an inputassessment image on the second display unit 40 on the basis of anassessment result from the determination unit 32. For example, thesecond display unit 40 may form a plurality of types of imagesselectively on the basis of an assessment result from the determinationunit 32; in this case, the second display controller 33 controls formingthe relevant type of image. In other words, the second display unit 40may activate a light source corresponding to the assessment result toform a different image according to the assessment result when thedetermination unit 32 assesses that the user movement detected by themovement detector 20 is an input action. That is, the second displayunit 40 may activate a light source to present an image corresponding tothe assessment result when the user movement corresponds to an inputaction.

The display controller 31 also controls the presentation of an inputassessment image on the display unit 10 on the basis of an assessmentresult from the determination unit 32. For instance, the displaycontroller 31 may control the light source 12 to emit a brighter lightwhen the determination unit 32 determines that the user movementdetected by the movement detector 20 is an input action.

FIG. 6 is a perspective view of the above-mentioned input device 2 inuse; in the example illustrated in FIG. 6 the light guide plate 11 andthe light source 12 produce a two-dimensional image of a rectangle,i.e., an input location image P1 in a space. The user may provide inputto the input device 1 by performing a predetermined input action at thelocation of the input location image P1; more specifically, the user mayprovide input as if touching the input location image P1 with the handH. The light guide plate 41 and the light source 42 cause an inputassessment image P2 to be presented in a space with the input assessmentimage P2 representing the assessment result for the input actionperformed by the user.

Note that in the example illustrated in FIG. 6 the light guide plate 41in the second display unit 40 is stacked more toward the positive X axisdirection than the light guide plate 11 in the display unit 10. However,the light guide plate 11 may be stacked further toward the positive Xaxis direction than the light guide plate 41 in the input device 2.Additionally, the light guide plate 41 need not necessarily be stackedon the light guide plate 11. However, preferably the light guide plate41 and the light guide plate 11 are stacked to reduce the size of theinput device 2.

FIG. 7A is an example of a three-dimensional image presented when theassessment result of a determination unit is presented as athree-dimensional image; FIG. 7A depicts two types of three-dimensionalimage. To present a three-dimensional image, for instance, the seconddisplay unit 40 may be provided with the number of light guide plates 41and light sources 42 respectively commensurate with the types of imagesto be presented for producing light incident on the light guide plates.However, the second display unit 40 is not required to have the numberof light guide plates 41 equal to the types of images to be presented.

FIG. 7B is an example of a second display unit 40 capable of presentingtwo types of three-dimensional images via a single light guide plate 41.The second display unit 40 illustrated in FIG. 7B includes a singlelight guide plate 41 and a light source 42 a and a light source 42 b.Light emitted from the light source 42 a is guided through only oneregion A1 that is a portion of the light guide plate 41. Light emittedfrom the light source 42 b is guided through only one region A2 that isa portion of the light guide plate 41. The regions A1 and A2 includeoptical-path changing portions (not shown) that present mutuallydistinct three-dimensional images. In other words, the light sources 42a and 42 b corresponding to mutually different three-dimensional images.Therefore, switching between the light sources 42 a and 42 b in thesecond display unit 40 allows two types of mutually differentthree-dimensional images to be presented. Note that the second displayunit 40 may be provided with three or more light sources whereby lightincident therefrom is guided via mutually different regions of the lightguide plate, thereby allowing the second display unit 40 to presentthree or more types of three-dimensional images.

FIG. 8A illustrates an example configuration of the second display unit40 when an assessment result from the determination unit 32 is presentedas a two-dimensional image. A plurality of images may be shown using asingle light guide plate when presenting a two-dimensional image. Inthis case the second display unit 40 includes a plurality of lightsources 42, and the light guide plate 41 that directs light enteringfrom the plurality of light sources 42 and causes the light to exittherefrom and form images in a space. The movement detector 20 maydetect input actions, and in this case the second display unit 40activates the light source 42 corresponding to the aforementioned inputaction to form a different image in a space in accordance with the inputaction. The second display unit 40 illustrated in FIG. 8A is providedwith a light guide plate 41 capable of presenting eight types oftwo-dimensional images and light sources 42 a-42 h (i.e., second lightsources) corresponding to each of the two-dimensional images.

The light sources 42 a-42 h are such that light therefrom enters thelight guide plate 41 from different directions or at differentlocations. In the example illustrated in FIG. 8A, light from each pair(i) through (iv) of light sources (i.e., (i) light sources 42 a and 42b; (ii) light sources 42 c and 42 d; (iii) light sources 42 c and 42 f;and (iv) light sources 42 g and 42 h) enter the light guide plate 41from different directions. Light from the light sources 42 a, 42 b enterthe light guide plate 41 from the same direction, and the light sources42 a, 42 b are isolated from each other. In the example illustrated inFIG. 8A, the light sources in each of the above mentioned pairs providelight that enter the light guide plate 41 from the same direction withthe light sources isolated from each other.

FIG. 8B is a perspective view illustrating a configuration of theoptical-path changing portions 16. The optical-path changing portions 16on the light guide plate 41 cause different input assessment images tobe presented in accordance with the direction and location at whichlight is incident on the light guide plate. The optical-path changingportions 16 include a reflection surface 16 a that reflects (totallyreflects) light incident thereon, and a vertical surface 16 b thattransmits incident light. Light L1 incident on the reflection surface 60a is totally reflected, and produces the two-dimensional image presentedon the second display unit 40. In contrast, light L2 incident on thevertical surface 16 b passes through the optical-path changing portion16, or is reflected opposite the direction that light reflected from thereflection surface 16 a produces the two-dimensional image. The seconddisplay controller 33 activates the light sources 42 a-42 hcorresponding to the incidence direction and incidence location thatwill present an input assessment image corresponding to the assessmentresult from the determination unit 32 and thereby causes the relevantinput assessment image to be presented.

As is above described, the second display unit 40 in the input device 2shows an input assessment image representing the assessment result fromthe determination unit 32. Accordingly, a user may reference the inputassessment image to verify whether or not the input action was assessedas the desired input.

The light sources 42 a-42 h and the light guide plate 41 may also beprovided to the second display unit 40. Therefore, the assessment resultfrom the determination unit 32 may be presented via an input assessmentimage formed in a space by the second display unit 40.

Note that the assessment result from the determination unit 32 does notneed to be presented as an image formed in a space; the assessmentresult may be presented, for instance, on a display device such as aliquid crystal display, or the like.

Modification Example

The second display device 40 may show an image that is identical to theinput location image presented on the display unit 10 where the image islarger than the image presented on the display device 10. In this case,the input action for changing the display size of the input locationimage may be preliminarily set in the input device 2. When the movementdetector 20 detects the aforementioned input action, the input device 2ends presentation of the input location image on the display unit 10 andbegins presentation of the input location image on the second displayunit 40.

Third Embodiment

Another embodiment of the present invention is described below indetail. In the embodiment described, an input device 3 (i.e., a gestureinput device) is installed in a vehicle. The input device 3 isconfigured identically to the input device 1. The input device 3 may beconfigured identically to the input device 2.

FIG. 9 is a perspective view of the input device 3 in use according tothis embodiment. As illustrated in FIG. 9, the display unit 10 and themovement detector 20 of the input device 3 is provided in a centerconsole of the vehicle. The input location image P1 is also presentednear the center console. The input device 3 is configured identically tothe input device 2; that is, the input device 3 may include the seconddisplay unit 40. In this case, the second display device 40 is alsoprovided in the vehicle center console. The determination unit 32 in theinput device 3 may be implemented as a function included in a controldevice in the vehicle. An input device 3 thusly configured may allow auser to provide input to the vehicle.

Fourth Embodiment

Another embodiment of the present invention is described below indetail.

Without being limited to the above described vehicle, the input device 1may be adopted in various kinds of electronic devices that accept inputfrom a user. Additionally, the input device 2 may be adopted in variousdevices instead of the input device 1.

FIG. 10A illustrates an example of the input device 1 installed in anelevator 200. The display device 10 and the movement detector 20 of theinput device 1 are provided, for instance, near the door 210 of theelevator 200. A user may perform an input action in the input locationimage P1 presented by the display unit 10 to perform an operation suchas opening or closing the door 210.

FIG. 10B illustrates an example of the input device 1 installed in arefrigerator 300. The refrigerator 300 includes a door 310 to thefreezer unit, and a door 320 to the refrigerator unit. The displaydevice 10 and the movement detector 20 of the input device 1 areprovided near the door handles of each door 310 and 320. The user mayperform an input action in the input location image P1 presented by thedisplay unit 10 to manipulate, for instance, the temperature of thefreezer unit and the refrigerator unit, the operation mode, or the like.

FIG. 10C illustrates an example of the input device 1 installed in agame machine 400. The display device 10 and the movement detector 20 ofthe input device 1 are provided near the center of the surface facingthe user. The user may perform an input action in the input locationimage P1 presented by the display unit 10 to manipulate an effectpresented on the game machine 400 (e.g., a gesture input in accordancewith a message presented on a liquid crystal display in the game machine400, or manipulate the reel while slot effects are being presented) ormanipulate the speed or direction for launching a pinball.

The input device 1 may also be installed in a television or an audiodevice, for instance. In this case the user may perform an input actionin the input location image P1 presented by the display unit 10 toperform an operation such as changing the channel or the volume.

The input device 1 may also be installed in a photo frame. In this casethe user may perform an input action in the input location image P1presented by the display unit 10 to perform an operation such aschanging the image to be shown.

The input device 1 may also be installed in a digital camera. In thiscase the user may perform an input action in the input location image P1presented by the display unit 10 to perform an operation such asmagnifying or reducing the image capture region, and capturing an image.

Additionally, the input device 1 may be installed in an air conditioningdevice (air conditioner). In this case the user may perform an inputaction in the input location image P1 presented by the display unit 10to perform an operation such as (1) setting the air temperature, or (2)changing the operation mode to cooling or heating.

The input device 1 may also be installed on a tablet. In this case theuser may perform an input action in the input location image P1presented by the display unit 10 to perform any desired operationpreliminarily associated with the aforesaid input action. In otherwords, the input device 1 may also function as a general purpose inputdevice.

Note that each of these devices may further include a separate displaydevice such as a liquid crystal display or the like. In this case thedisplay unit 10 in the input device 1 may be superimposed on the liquidcrystal display and controlled to magnify the contents displayed on theliquid crystal display and form an image in that space.

Fifth Embodiment

Another embodiment of the present invention is described below indetail.

In each of the above-described embodiments the input devices 1-3 includethe display unit 10 illustrated in FIG. 2. However, the input devices1-3 may include the below-described display unit 10A, 10B, or 10Cinstead of the display unit 10 or the second display unit 40.

Display Unit 10A

FIG. 11A is a cross-sectional view illustrating a configuration of thedisplay unit 10A (i.e., an image projector). As illustrated in FIG. 11A,the display unit 10A includes a light source 12, and a light guide plate15 (i.e., a first light guide plate). FIG. 11B is a plan viewillustrating a configuration of the light guide plate 15 in the displayunit 10A.

The light guide plate 15 guides light entering from the light source 12(i.e., incident light). The light guide plate 15 is produced from atransparent resin material with a relatively high index of refraction.The light guide plate 15 may be produced using, for instance, apolycarbonate resin, a poly methyl methacrylate resin, glass or thelike. In this embodiment the light guide plate 15 is produced from apoly methyl methacrylate resin. The light guide plate 15 includes anemission surface 15 a (i.e., a light emitting surface), a rear surface15 b, and an incidence surface 15 c as illustrated in FIG. 11A.

The emission surface 15 a outputs light that is guided by the lightguide plate 15 and modified by an optical-path changing portion 16identical to the optical-path changing portions described in the secondembodiment. The emission surface 15 a is configured as the front surfaceof the light guide plate 15. The rear surface 15 b and the emissionsurface 15 a are mutually parallel, and the later-described optical-pathchanging portion 16 is arranged thereon. Light emitted from the lightsource 12 is incident on the light guide plate 15 at the incidencesurface 15 c.

Light emitted from the light source 12 and entering the light guideplate 15 from the incidence surface 15 c is totally reflected betweenthe emission surface 15 a and the rear surface 15 b and guided throughthe light guide plate 15.

As illustrated in FIG. 11A, an optical-path changing portion 16 isformed on the rear surface 15 b inside the light guide plate 15; theoptical-path changing portion 16 changes the optical path of lightguided through the light guide plate 15 and causes the light to exitfrom the emission surface 15 a. A plurality of optical-path changingportions 16 is provided on the rear surface 15 b of the light guideplate 15.

The optical-path changing portions 16 are provided along a directionparallel to the incidence surface 15 c. The optical-path changingportions 16 are tetrahedrons provided with reflection surfaces 16 a thatreflect (totally reflect) light entering the light guide plate. Forexample, the optical-path changing portions 16 may be recesses formed inthe rear surface 15 b of the light guide plate 15. Note that theoptical-path changing portions 16 are not limited to being tetrahedrons.As illustrated in FIG. 11B, the plurality of optical-path changingportions 16 may be made up of a plurality of groups of optical-pathchanging portions 17 a, 17 b, 17 c formed on the rear surface 15 b ofthe light guide plate 15.

The plurality of optical-path changing portions 16 in each group ofoptical-path changing portions 17 a, 17 b, 17 c are arranged on the rearsurface 15 b of the light guide plate 15 so that the angles of thereflection surfaces 16 a are mutually different in relation to thedirection from which light is incident. Thus, each group of optical-pathchanging portions 17 a, 17 b, 17 c changes the optical path of theincident light and causes the light to exit in various directions fromthe emission surface 15 a.

Next, the method of how the display unit 10A forms the stereoscopicimage I is described with reference to FIG. 12. In this case the planeperpendicular to the emission surface 15 a of the light guide plate 15is the stereoscopic image forming plane P, and light modified by theoptical-path changing portions 16 form a stereoscopic image I as aplanar image in the stereoscopic image forming plane P.

FIG. 12 is a perspective view illustrating how the display unit 10Aproduces the stereoscopic image I. Note that in the case described, thestereoscopic image I formed in the stereoscopic image forming plane P isa circle with an oblique line therethrough.

As illustrated in FIG. 12, the optical-path changing portions 16 from agroup of optical-path changing portions 17 a may change the optical pathof light in the display unit 10A so that the modified light intersectswith the lines La1 and La2 in the stereoscopic image forming plane P.Hereby a line image LI, which is a portion of the stereoscopic image Iis formed in the stereoscopic image forming plane P. The line image LIis parallel to the YZ plane. Thus, light from multiple optical-pathchanging portions 16 belonging to the group of optical-path changingportions 17 a create a line image LI from the line La1 and the line La2.Light creating an image of the line La1 and the line La2 only needoptical-path changing portions 16 in the group of optical-path changingportions 17 a.

Similarly, light whose optical path changes due to the optical-pathchanging portions 16 in a group of optical-path changing portions 17 bintersect with the lines Lb1, Lb2, and Lb3 in the stereoscopic imageforming plane P. Hereby a line image LI, which is a portion of thestereoscopic image I is formed in the stereoscopic image forming planeP.

Light whose optical path changes due to the optical-path changingportions 16 in a group of optical-path changing portions 17 c intersectswith the lines Lc1 and Lc2. Hereby a line image LI, which is a portionof the stereoscopic image I is formed in the stereoscopic image formingplane P.

The groups of optical-path changing portions 17 a, 17 b, 17 c . . . formline images LI at mutually different positions along the X axisdirection. Reducing the distance between the groups of optical-pathchanging portions 17 a, 17 b, 17 c . . . in the display unit 10A reducesthe distance between the line images LI produced by the groups ofoptical-path changing portions 17 a, 17 b, 17 c . . . along X axisdirection. As a result, the optical-path changing portions 16 in thegroups of optical-path changing portions 17 a, 17 b, 17 c . . . in thedisplay unit 10A change the optical path of light whereby grouping theplurality of line images LI created by this light forms a stereoscopicimage I as a planar image in the stereoscopic image forming plane P.

Note that the stereoscopic image forming plane P may be perpendicular tothe X axis, perpendicular to the Y axis, or perpendicular to the Z axis.Additionally, the stereoscopic image forming plane P may be non-verticalrelative to the X axis, the Y axis, or the Z axis. Moreover, thestereoscopic image forming plane P may be curved instead of a flatplane. In other words, the display unit 10A may form a stereoscopicimage I in any desired plane in space (flat or curved) by way of theoptical-changing portions 16. A three-dimensional image may thus beformed by a combination of a plurality of planar images.

Display Unit 10B

FIG. 13A is a perspective view of a display unit 10B (i.e., an imageprojector); FIG. 13B is a cross-sectional view depicting a configurationof the display unit 10B.

As illustrated in FIG. 13A and FIG. 13B, the display unit 10B includesan image display device 81 (i.e., first light source); an image forminglens 82, a collimating lens 83, a light guide plate 84 (i.e., firstlight guide plate), and a mask 85. The image display device 81, theimage forming lens 82, the collimating lens 83, and the light guideplate 84 are arranged in this order along the Y axis direction. Inaddition, the light guide plate 84 and the mask 85 are arranged in thisorder along the X axis direction.

The image display device 81 presents a two-dimensional image that isprojected in a space via the display unit 10B in the display area inaccordance with an image signal received from a control device (notshown). The image display device 81 is, for instance, a typical liquidcrystal display that is capable of outputting image light by displayingan image in a display region. In the example depicted, the displayregion of the image display device 81 and the incidence surface 84 awhich faces said display region in the light guide plate 84 are botharranged parallel to the XZ plane. The rear surface 84 b and theemission surface 84 c (i.e., a light emitting surface) in the lightguide plate 84 are arranged parallel to the YZ plane. The emissionsurface 84 b, which emits light onto the mask 85, faces the rear surface84 c whereon prisms 141 (later described) are provided. Additionally,the surface whereon slits 151 are provided in the mask 85 (laterdescribed) is parallel to the YZ plane. Note that the display region inthe image display device 81 and the incidence surface 84 a in the lightguide plate 84 may face each other, or the display region in the imagedisplay device 81 may be inclined relative to the incidence surface 84a.

The image forming lens 82 is disposed between the image display device81 and the incidence surface 84 a. Image light exits the image displaydevice 81 and enters the image forming lens 82, and the image forminglens 82 focuses the image light in the XZ plane; the image light exitsthe image forming lens 82 and enters the collimating lens 83. Note thatthe XY plane is parallel to the length of the incidence surface 84 a.The image forming lens 82 may be of any type so long as it is capable offocusing the image light. The image forming lens 82 may be a bulk lens,a Fresnel lens, a diffraction lens, or the like. The image forming lens82 may also be a combination of a plurality of lenses arranged along theY axis direction.

The collimating lens 83 is disposed between the image display device 81and the incidence surface 84 a. The collimating lens 83 collimates theimage light focused by the image forming lens 82 onto the XY plane; theXY plane is orthogonal to the length of the incidence surface 84 a.Collimated light exiting the collimating lens 83 enters the incidencesurface 84 a of the light guide plate 84. Similarly to the image forminglens 82, the collimating lens 83 may be a bulk lens, or a Fresnel lens.The image forming lens 82 and the collimating lens 83 may be arranged inthe opposite order. Additionally, the functions of the image forminglens 82 and the collimating lens 83 may be achieved through a singlelens or though a combination of multiple lenses. In other words, thecombination of the image forming lens 82 and the collimating lens 83 maybe configured in any manner so long as the image light output from thedisplay region of the image display device 81 converges in the XZ plane,and collimated in the XY plane.

The light guide plate 84 is a transparent resin; image light collimatedby the collimating lens 83 enters the light guide plate 84 at theincidence surface 84 a and exits the light guide plate 84 from theemission surface 84. In the example depicted, the light guide plate 84is a flat rectangular panel with the surface facing the collimating lens83 and parallel to the XZ plane taken as the incidence surface 84 a. Therear surface is taken as the surface parallel to the YZ plane andlocated in the negative X axis direction while the emission surface 84 cis taken as the surface parallel to the YZ plane and facing the rearsurface 84 b. A plurality of prisms 141 (i.e., emitting structures,optical-path changing portions) is provided in light guide plate 84.

The plurality of prisms 141 reflects the image light entering the lightguide plate from the incident surface 84 a. The prisms 141 are providedon the rear surface 84 b of the light guide plate 84 protrudingtherefrom toward the emission surface 84 c. For example, if image lightpropagates along the Y axis direction, the plurality of prisms 141 maybe substantially triangular grooves with a predetermined width in the Yaxis direction (e.g., 10 μm) and arranged at a predetermined intervalalong the Y axis direction (e.g., 1 mm). The prisms 141 include areflective surface 141 a, which is the optical surface closer to theincidence surface 84 a relative to the direction along which the imagelight travels (i.e., the positive Y axis direction). In the exampledepicted, the plurality of prisms 141 is provided parallel to the Z axison the rear surface 84 b. Thus, the reflection surfaces 141 a in theplurality of prisms 141 are provided parallel to the Z axis andorthogonal to the Y axis; the reflection surfaces 141 a reflect theimage light entering from the incidence surface 84 a and propagatingalong the Y axis direction. Each of the plurality of prisms 141 causesimage light emitted from mutually different positions in the displayregion of the image display device 81 along the direction orthogonal tothe length of the incidence surface 84 a (i.e., the Y axis) to exit fromthe emission surface 84 c. That is the prisms 141 allow image light toexit from one surface of the light guide plate 84 toward a predeterminedviewpoint 100. Details of reflection surfaces 141 a are described later.

The mask 85 is configured from a material that is opaque to visiblelight and includes a plurality of slits 151. The mask 85 only allowslight emitted from the emission surface 84 c of the light guide plate 84and oriented toward the image forming point 101 in a plane 102 to passtherethrough via the plurality of slits 151.

The plurality of slits 151 only allows light emitted from the emissionsurface 84 c of the light guide plate 84 that is oriented towards theimage forming point 101 in a plane 102 to pass therethrough. In theexample depicted, the plurality of slits 151 is provided parallel to theZ axis. 2 b Individual slits 151 may also correspond to any prism 141 inthe plurality of prisms 141.

When configured as above described, a display unit 10B forms andprojects the image presented by the image display device 81 onto animaginary plane 102 outside the display unit 10B. More specifically,image light emitted from the display region in the image display device81 passes through the image forming lens 82 and the collimating lens 83,whereafter the image light enters the incidence surface 84 a which isone end surface of the light guide plate 84. Subsequently, the imagelight incident on the light guide plate 84 propagates therethrough andarrives at the prisms 141 provided on the rear surface 84 b of the lightguide plate 84. The reflection surfaces 141 a reflect the image lightarriving at the prisms 141 toward the positive X axis direction andthereby causes the image light to exit the light guide plate 84 from theemission surface 84 c which is parallel to the YZ plane. The image lightemitted from the emission surface 84 c and passing through the slits 151of the mask 85 form an image of the image forming point 101 in the plane102. In other words, image light emanating from points in the displayregion of the image display device 81 converge in the XZ plane,collimate in the XY plane and thereafter is projected onto an imageforming point 101 in a plane 102. The display unit 10B processes all thepoints in the display region in the aforementioned manner to therebyproject an image output in the display region of the image displaydevice 81 onto the plane 102. Thus, when a user views this imaginaryplane 102 from a viewpoint 100, the user perceives the image that isprojected in air. Note that the plane 102 whereon the projected image isformed is a virtual plane; however, a screen may be disposed in theplane 102 to improve visibility.

Display Unit 10C

FIG. 13B is a cross-sectional view depicting a configuration of thedisplay unit 10C. Instead of merely eliminating the mask 85 from thedisplay unit 10B, the display unit 10C modifies the configuration of theprisms in the light guide plate 84. Only the differences from the aboveconfigurations are described below.

The angle α between the reflection surface of a prism 141 and the rearsurface 84 b in the display unit 10C increases with distance from theincidence surface 84 a. Note that the angle α of the prism 141 that isfurthest from the incidence surface 84 a is preferably an angle thatcauses total reflection of light in the image display device 81.

Light emanates from a point on the display region of the image displaydevice 81 and oriented toward a predetermined viewpoint such as theviewpoint 100 a or the viewpoint 100 b; with the angles configured asabove described the closer this emanation point is to the rear surface84 b i.e., more toward the X axis direction, the further away the prism141 from the incidence surface 84 a that reflects this light. However,without being limited to this configuration, it is sufficient to map alocation in the X axis direction on the display region of the imagedisplay device 81 to a prism 141. In the display unit 10C, prisms 141farther from the incidence surface 84 a also reflect light more towardthe incidence surface 84 a. Whereas, prisms 141 closer to the incidencesurface 84 a reflect light more toward a direction away from theincidence surface 84 a. Therefore, the display unit 10C is capable ofemitting light from the image display device 81 toward a specificviewpoint even without the mask 85. The display unit 10C projects lightexiting from the light guide plate 84 to form an image in a planeperpendicular to the X axis direction so that the image diffuses inaccordance with distance from the plane in the X axis direction. Giventhat as a result the display unit 10C may create a parallax effect inthe X axis direction whereby an observer may align both eyes along the Xaxis direction to stereoscopically view an image projected in the X axisdirection.

Given that none of the light reflected by the prisms 141 and orientedtowards the [desired] viewpoint is blocked in the display unit 10C, anobserver may see an image presented on the image display device 81 andprojected in the air even if the observer's viewpoint moves along the Yaxis direction. However, the angle between light rays from the prisms141 oriented toward the viewpoint and the reflection surface of theprisms 141 changes with the location of the viewpoint along the Y axisdirection; therefore, the position of the viewpoint in the image displaydevice 81 corresponding to the light ray also changes with the locationof the viewpoint along the Y axis direction.

For instance, when viewed from the viewpoint 100 a, light from each ofthe points 81 a-81 c in the image display device 81 are reflected byprisms 141-1, 141-2, 141-3 respectively to form an image on theprojection plane 102 a (with points 81 a, 81 b, 81 c in order from theobserver; and prisms 141-1, 141-2, 141-3, 141-4 in order from theincidence surface 84 a toward the far end).

In contrast, assume that the observer's eyes move to the viewpoint 100 bwhich is further from the incidence surface 84 a that the viewpoint 100a. In this case, at viewpoint 100 b the observer may observe lightemitted from the light guide plate 84 toward a direction further awayfrom the incidence surface 84 a than at viewpoint 100 a.

The angle α between the reflection surface of a prism 141 and the rearsurface 84 b in the display unit 10C increases with distance from theincidence surface 84 a. Therefore, for example the light from each ofthe points 81 a-81 c is reflected by the prisms among prisms 141-1-141-4that are closer to the incidence surface 84 a forms an image in theprojection plane 102 b and then travels toward the viewpoint 100 b.Consequently, even if the observer's viewpoint changes along the Y axisdirection, the location of the projected image hardly shifts.Additionally, in this example light from each of the points in the imagedisplay device 81 is also formed in the Y axis direction to some extentdue to the prisms 141. Therefore, an observer with both eyes alignedalong the Y axis direction may also view a stereoscopic type image.

Moreover, the display unit 10C does not use a mask; therefore, thisreduces the loss of light intensity and allows for a brighter image tobe projected into a space. Additionally, since the display unit 10C doesnot use a mask, an object behind the light guide plate 84 (not shown)and the projected image may both be perceived by an observer.

When configured as above described, similar to the display unit 10B, thedisplay device 10C forms and projects the image presented by the imagedisplay device 81 onto an imaginary plane 102 outside the display unit10C.

The present invention is not limited to each of the above describedembodiments, and may be modified in various ways and remain within thescope of the claims. The technical means disclosed in each of thedifferent embodiments may be combined as appropriate, and an embodimentobtained in such a manner remains within the technical scope of thepresent invention.

1. A gesture input device comprising: a movement detector that detects auser movement; and an image projector that forms a zone image in a spaceto present a region whereat the movement detector detects movement; theimage projector including: a first light source; and a first light guideplate comprises a light emitting surface and directs light entering fromthe first light source so that the light exits from the light emittingsurface and forms an image in a space.
 2. The gesture input deviceaccording to claim 1, further comprising: a determination unit thatassesses whether or not the movement detected by the movement detectoris an input action representing a predetermined input; and an assessmentresult presentation unit that presents an assessment result from thedetermination unit.
 3. The gesture input unit according to claim 2, withthe assessment result presentation unit comprising: a second lightsource; and a second light guide plate that directs light entering fromthe second light source so that the light exits therefrom and forms animage in a space.
 4. The gesture input device according to claim 3,wherein the second light guide plate and the first light guide plate arestacked.
 5. The gesture input unit according to claim 2, with theassessment result presentation unit comprising: a plurality of secondlight sources; and a second light guide plate that directs lightentering from the plurality of second light sources so that the lightexits therefrom and forms an image in a space; and when the movementdetected by the movement detector is an input action representing apredetermined input, the assessment result presentation unit activates asecond light source among the plurality of second light sourcescorresponding to said input action to cause a different imagecorresponding to the input action to be formed in a space.
 6. Thegesture input device according to claim 5, wherein the direction fromwhich light is incident on the second light guide plate is different forthe plurality of second light sources.
 7. The gesture input deviceaccording to claim 5, wherein the direction from which light is incidenton the second light guide plate is the same for the plurality of secondlight sources and the second light sources are mutually isolated.